"There were missteps and miscommunications, procedures not followed and poor decisions," NTSB Chairman Deborah A.P. Hersman said in a written statement."There were multiple points where this catastrophe could have been averted, but it was not."

Contributing to the derailment, the NTSB said, was CN's failure to work with Winnebago County to develop a comprehensive storm water management design to address previous washouts in 2006 and 2007 and the company's failure to issue a flash-flood warning to the train crew.

The NTSB also pointed to flaws in the tank cars, which made them susceptible to "damage and catastrophic loss of hazardous materials," according to the report.